1. Field of the Invention
The present invention relates to computer control of a system consisting of a plurality of facilities, such as an automated factor. More particularly, it relates to a facilities control method (hereinbelow, called "condition discriminative process") wherein the status of each of respective facilities is received, conditions are analyzed in accordance with predetermined control logic functions and, when the conditions have been satisfied, operation commands based upon the control logic functions are issued to the respective facilities.
2. Description of the Prior Art
In general, the aforementioned condition discriminative control process employs a system wherein control logic functions for analyzing conditions and generating control commands are programmed by the use of a general-purpose language, such as assembler language, and are executed in a control apparatus. In this case, the design of software, including the study of a program table as well as a program processing system, is carried out separately from the study of the control logic functions themselves. Herein consideration software development is required for realizing the control logic functions devices by a control engineer to yield an error-free program, and there is the problem that special personnel for carrying out the programming are required. In addition, documents (specifications, design drawings, etc) are required for the maintenance of the program. A further problem is that, even when these documents are utilized, the program cannot be effectively modified by an unskilled person.
For saving the labor required for program development, a decision table which contains control logic operations are complicated, the number of conditions to be employed in the decision table becomes large, and it is very difficult to take a survey of all available logic and arrange the condition entries so as to accurately realize the control logic functions. Further, in changing the control logic functions, it is next to impossible to read the present control logic functions from the contents of the table and amend them appropriately. There is also a format in which a condition entry or action entry is describable in natural language so as to enhance the understanding of the control logic function, as described in an article by E. H. Mamdani entitled "A Fuzzy Rule-Based Method of Controlling Dynamic Process", Proceedings of the 20th IEEE Conf. on Decision and Control, pp. 1098-1103, DecEMBER 1981. In this case, however, the method of expressing the control logic function is similar to that of the decision table, and all necessary conditions must be arranged and provided for individual actions. Accordingly, it is difficult to describe and change complicated control logic functions.